S2io: Change kmalloc+memset to k[zc]alloc

- Changed kmalloc+memset to k[zc]alloc as per Mariusz's patch
  <m.kozlowski@tuxland.pl>

Signed-off-by: Sivakumar Subramani <sivakumar.subramani@neterion.com>
Signed-off-by: Ramkrishna Vepa <ram.vepa@neterion.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>